While gardeners may still have several more weeks to enjoy what’s left of the growing season, it will soon be time to put our gardens to bed for winter.
Flowers and vegetables whose foliage has begun to brown and shrivel should generally be removed before winter. Removing the spent foliage is an excellent way to reduce the chance for fungi and insect pests to over winter.
Herbaceous perennials should be cut back to just above the crown of the plant, the place where the stems join the roots. Annual plants should be completely removed from the garden. Plant refuse can be composted to recycle into organic matter to add to the garden soil next year.
Obviously, some plants, such as ornamental grasses, provide winter interest in their dried state. In areas where the soil is prone to erosion by wind or water, such as on a slope, leaving the dead stems can help hold soil in place. In these cases, plants can be left until later winter or early spring. Make sure to cut back the dead stems before the new foliage comes up.
Pruning of trees and shrubs is generally best left until late winter or spring for most plants. Pruning in fall will leave the cut stems vulnerable to further dieback at the cuts, and, in some years, may encourage buds to sprout during mild weather. Dead or damaged limbs can be removed any time.
Clean up of fallen tree leaves may be needed, especially around mature, large-leaved trees, such as maple, oak and sycamore. But autumn leaves can easily be turned into valuable, soil-enhancing organic matter.
Dry leaves can be plowed or tilled under in the vegetable or annual flower beds, in fall, to provide a source of organic matter. Shredding the leaves first will speed the breakdown, so that the leaves will not be visible by spring. Be sure to mix the leaves into the soil, rather than leaving them on top through the winter, to avoid keeping the soil too cold and wet to work in the spring.
Tree leaves can be recycled directly on the lawn. Use your power mower or shredder/vacuum to break dry leaves up into smaller pieces. A mulching blade on the mower will speed this process, but even a standard blade will do an adequate job. For large leaves like maple and sycamore, it may take several passes to get a finely shredded product. Once the leaves are pulverized, they will break down quickly. A fall application of nitrogen fertilizer (about 1 pound of nitrogen per 1,000 square feet) will help speed decomposition of the leaves and also will benefit the grass plants.
Fall leaves also make great composting ingredients, especially when mixed with green trimmings and grass clippings. Again, the smaller the pieces, the faster they’ll break down, so shred or chop dry leaves before adding them to the compost pile. If you don’t have green trimmings or grass clippings, add a source of nitrogen to the leaves, such as commercial fertilizer or dry cow, horse, sheep or poultry manure.
Last, but not least, shredded leaves can be used as a winter mulch to protect tender perennials through the coming harsh weather. Shredding the leaves will help prevent them from packing down as they get wet and smothering the plants that they are supposed to protect. To provide winter protection, apply a 3-6 inch layer of shredded leaves over the top of tender perennials after several hard freezes. The goal of winter mulch is to keep plants dormant through the winter, so it must be applied after the ground is cold and plants are fully dormant. The timing of application will vary from year to year with the weather, but generally will be appropriate sometime between the Thanksgiving and Christmas holidays.